One of the main concerns of the automobile companies is the development of an eco-friendly vehicle. Recently, automobile companies have been developing a variety of eco-friendly vehicles to conform to user demands and government regulations, and the most noteworthy eco-friendly vehicle is an electric vehicle. The chief obstacle in the development of the electric vehicle depends upon whether new system components maintain durability in the environmental conditions of the vehicle. An example of such system components includes a high-voltage battery for charging. Degradation in durability for each charge condition of such a high-voltage battery may be a problem. FIGS. 1 and 2 show a use range of SOC (State of Charge) and a charge process of the high-voltage battery in the electric vehicle.
The following Table 1 indicates an available range of SOC, a size of charge current, and a drivable distance based on a charging method of the electric vehicle with reference to the graph shown in FIG. 1.
TABLE 1Available rangeSize ofCharging methodof SOCCharge currentDrivable distanceSlow charge~95%LowLargeQuick charge~80%HighSmall
That is, the vehicle may be charged in a manner of quick charge or slow charge based on ambient charge environments. The quick charge may perform charge at substantially high current for a predetermined short time and the slow charge may perform charge at substantially low current for an increased longer predetermined period of time. In other words, the battery may be charged up to high SOC (e.g., SOC about 95%) during the slow charge and may be charged up to low SOC (e.g., SOC about 80%) during the quick charge.
FIG. 2 shows an exemplary diagram understanding of the description. Referring to FIG. 2, whether a quick charge is the current charge may be determined (S210), and in response to determining a quick charge, the battery may be charged up to a substantially low SOC at high current (S220). In addition, in response to determining a slow charge, the battery may be charged up to a substantially high SOC at low current (S230).
However, according to the above-mentioned method, usable energy of the battery may be determined based upon the charging method regardless of a user's intention. In addition, a charge depth (e.g., charge level) of the battery may directly affect durability of the battery. Particularly, a lithium battery applied to the electric vehicle may be vulnerable to degradation as an operational range of upper limit SOC is increased.